Shifting fulcrum valve for rock drills



Nw. 6, 192s. 1,690,810

L. .C. BAYLES `ET`AL SHIFTING FULCRUM VALVE FOR ROCK DRILLS Filed May 2.1. 1925 H .7 v v 3 JImE d z' www THEIR AT oRNEY Patented Nov. 6, 1928.

UNITED s'frATasg 1,690,810 PATENT? oFFIfcEf.-

LEWIS C. BAYLES AND FRED M. SLATER, EASTONLPENNSYLVANIA, SSIGRSKTO INGERSOLL-RAND COMPANY, OF'JER-SEY `CI'1Y,NE'\?V JERSEY, A CORPORATION OF NEW JERSEY. g f

ySHIFTING FULCRUM VALVE Foa Rooi; paints,

Application nled Mayl271925. SerialrrN'o. 33,119. l

yThis invention relates to fluid actuated rock drills, but more particularly to an improved plate-valve having a shifting fulcrum.

A plateor disk valve ofthe currentthrownv type for rock drills or other uses for distributing pressure fluid has been found to operate satisfactorily and well by the proper provision of a comparatively, large valve surface under or opposite `which the pressure is dropped when the exhaust port isopened by the piston, so that the pressureof the live pressure fluid and the `tendency of the pressure fluid to produce a` current'over the end of the valve quickly Closes the valve.

One of the objects of the present invention is to automatically increase Ythe valve area from' which thepressureis llargely removed, at the instant of time that such function is brought into operation. An oscillating valve, oscillating about aA fixed fulcrurn, has certain predetermined pressure areas throughout its Operation, but by shifting the fulcrum to one` side or the other as the valve oscillates, these areasrare automatically va- .ried on one side or ,the other of the fulcrum of the valve, and in addition the valve is automatically thrown out v,of balance so that greater leverage may be applied on the closing side to cause the valve to close more quickly. The valve is also prevented from flutterino:

Further objects of the invention will hereinafter appear and the .invention is illustrated in vthe* accompanying drawings, inA

. whichy Figure 1 is a.I longitudinal sectional elevation partly broken away of so much of a rock drill as will serve to make the invention clear,

Figure 2 is a transverse sectional view on the line Q-Qof Figure l looking upwardly in the direction of the arrows, but the ports K and L underneath the valve have been shown in dot and dash lines to show that they are centrally of the cylinder; c

The'valve F is arranged in theva'lve cham-f ber G in the head bloclrH and between the conveniently located in the position indicated valve and the cylinder is located the cylinder head plate J having the' inlet port'K leadingv port P at the forward end of the cylinder.. f

The 'valve F, for convenience of illustra-- tion, is shown in the form of a thin Hat disk circularin forni and uniformly tapering on itsupper or outer side from the median line or diameter Q-tothe periphery at each side R and S. The under or opposite side of the valve is provided with a central flat portion T extending between the points a and Z) indicated as lines in Figure 2. From the location of these lines L and o the valve is substantially uniformly taperedon both end surfaces and in opposite directions to the periphery at the ends R and The valve may or may not be undercut or recessed as indicated at c and CZ to lighten the valve.

In consequence of the valve construction described, the valve oscillates'oi rocks lirst on the fulcrum formed along the linea which is in effect a rib and then along the, line or rib b `as indicated in Figures Sand 4 so that the fulcrum shiftsl from the point a tothe point Z) and back again as the valve oscillates, and does not csc-illate about a central or median line. In consequence the/area of the surface, bounded by the .fulcrum line a and the periphery S of the valve atv one side of the fulcrum, is greater than the area. bounded by the linea and the periphery R' of the valve at the other side of the rfulcrum in the position indicated in Figure and this relative proportion of areas on opposite sides of `trolled only by the pistonand in this instance the fulcruin is Vreversed in Figure 4 when the v z -i i c a c fulcruin changes to the lineb.,

The valve chamber G in the head block H is circular in form and sullicient clearancey is provided between the valve and the Walls of the chamber tov permit free oscillation of` the valve. The valve may be guided in any suitable manner as by means of the pins U seated in the plate J and extending into'longivalve.

permit freedom of movement of the valve, without intertereneeor friction between the fulcrurn points and the guidingrneans.

The back head TN of the rock drill is provided with the throttle valve X controlling the supply of live pressure iluid to the valve chainber G. rlhe machine is provided with a compression relief valve Y having` the heads Z controlling the compression relief ports e and j] for relieving the compression at the ends ot' the cylinder after the i'iiain exhaust E is closed. This valve autoii'iatically actuated by means ot' the ports g and la. Y

In the operation or' the device, let it be assuined that the piston is at the Aend oi' 'its forward stroke and ltraveling rearwardly as indicated iii Fi'gure l. The live, pressureiluid in the` valve Chlaiiiber Gf holds the valve `in the position indicated and live pressure fluid is admitted over the periphery d ot the valve to tlieinliet port P at the forward end the cylinder to drive the piston rearwardly. After Vthe piston closes the exhaust port E, compression in the rearp/wirdl end oit` the cylinder is relieved through the compression relief port e. Then the piston B overruns and again opens the exhaust port E to the forward end of the cylinder, the compression relief valve Y is thrown forwardly by pressure acting through the port g andv since the forward end of the cylinder is then open to exhaust, the pressure is reduced or droppedY b neatli the valve F over tlie entire surface or' the valve from its i'ulcruinrto the periphery7 S so that the live pressure fluid' on top of the valve and compression pressure underneath the opposite end of the valve Causes the Avalve i tooscillate first about the fulcruin a and then the fulcruni isY shifted to the tulliriiin the valve closes the inlet port L coinnilunicat'- ing with the frontend' oi the cylinder. At the` saine time, theinliet port K to the rearend of the cylinder is opened and the piston starts oii'its forward stroke after which the cycle is repeated. y v v Y The `valve has Aa shifting ulcr'uin because the 'ruleruin sh' 'troni t t'o'iand vice versa v i l i l i i. or in other woi ds the valve may be said to have shitting` iulcrav to increase the leverage exerted by the pressure Huid onthe valve. This teature is accomplished by virtue of the tact that the tulcra mand?) are spaced 'liroin the center othe valveV The provision ot a flat portion T between the tulcra a and in? siires stability ofthe valve in its neutral position and Theclearance between tlieperipheiiy and permits a more even action ofthe S of the valve and the walls of the head block H fo'riiiing the valve casing,l as stated, is suticient to pernit free oscillation of the valve, but is purposely not excessive, and as shown in the drawings, isl sinall` enough to appreci ably cho'lie `orY restrict the passage of live motive fluid in passing over the periphery o' the valve. For this reason there will be a niarked drop` in the pressure underneath the raised side or wing oli' the valve as shown in Figure l, when tliepiston overruns and opens the niainy lexhaust port E on its rearward stroke. This drop in pressure olcours: quickly because of throttling of the live'ilnotive fluid in passing `over the periphery ot theL valve,

and the pressure drop is 'etlective underneath the ilve to close thev saine b virtue ol" the the valve; u i

We are not to be understood as liihiting tlie invention to tli'e precise foilnfalnfd: details' of construction shown in theE drawings because the drawings Vare merely illustrative of oil'e preferred iliea'ris ot' obtaining a shifting fulcruin. Obviously, equivale t constriltion's inay be devised those `sl illed in the art l'. A 'liiid actuated roelr drill, colhpr'isiii" a cylinder aiid rec'ipro'oatingpiston,V a cylinder exhaust pollt, a valve chest having a flat valve seat, a Vfluid actuated oscillating distributing valve iiil tlileiioilrnl f a tliili` plateforinedg with a l'attened central inediari portion and oppo'- sitely ext'e'iidiiig surtaes tapered with respect to said niedian portion, whereby tlhh @ages of saiuf median particu* f01-iiievdaii- Lewis o. Barres? FRED M. staren.

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